Orthogonal resource reuse with SDMA beams

ABSTRACT

A wireless communication system can implement beamforming across multiple omni-directional antennas to create beams at different spatial directions. The communication system can arrange the beams in sets, with each set arranged to provide substantially complete coverage over a predetermined coverage area. The communication system can arrange the multiple SDMA beam sets to support substantially complementary coverage areas, such that a main beam from a first set provides coverage to a weak coverage area of the second beam set. The wireless communication system assigns or otherwise allocates substantially orthogonal resources to each of the beam sets. The wireless communication system allocates resources to a communication link using a combination of beam sets and substantially orthogonal resources in order to provide improved coverage without a corresponding increase in interference.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/794,001, filed Apr. 20, 2006, entitled “ADAPTIVE RESOURCE REUSE INSDMA WIRELESS COMMUNICATION,” hereby incorporated by reference herein inits entirety.

BACKGROUND OF THE INVENTION

The present document relates generally to wireless communication andmore specifically to resource allocation in space-division multipleaccess (SDMA) wireless communication systems.

Wireless communication systems have become a prevalent means by which amajority of people worldwide has come to communicate. Wirelesscommunication devices have become smaller and more powerful in order tomeet consumer needs and to improve portability and convenience.Consumers have found many uses for wireless communication devices suchas cellular telephones, personal digital assistants (PDAs) and the like,demanding reliable service and expanded areas of coverage.

System capacity is a typical constraint that limits the ability of asystem to provide reliable service to communication devices within agiven coverage area. Wireless communication systems utilize varioustechniques that contribute to increasing system capacity.

Space Division Multiple Access (SDMA) is a technique that can beimplemented in a multiple antenna communication system. SDMA utilizesthe spatial dimension to support more terminals for data or informationtransmissions. The SDMA utilizes the spatial signatures of the terminalsand schedules multiple data transmissions on each link that have(ideally) orthogonal spatial signatures to one another.

A wireless communication system can implement SDMA in various ways. Onemethod is to utilize beamforming or otherwise directional antennapatterns. However, SDMA systems utilizing beamformed or otherwisedirectional antenna may suffer from weak coverage areas between beams orincreased interference due to overlapping beams.

BRIEF SUMMARY OF THE INVENTION

A wireless communication system can implement beamforming acrossmultiple omni-directional antennas to create beams at different spatialdirections. The communication system can arrange the beams in sets, witheach set arranged to provide substantially complete coverage over apredetermined coverage area. The communication system can arrange themultiple SDMA beam sets to support substantially complementary coverageareas, such that a main beam from a first set provides coverage to aweak coverage area of the second beam set.

The wireless communication system assigns or otherwise allocatessubstantially orthogonal resources to each of the beam sets. Thesubstantially orthogonal resources can be, for example, time, frequency,code, and the like, or some combination thereof.

The wireless communication system allocates resources to a communicationlink using a combination of beam sets and substantially orthogonalresources in order to provide improved coverage without a correspondingincrease in interference. For example, the wireless communication systemcan assign a beam from a beam set and the frequency or other orthogonalresource corresponding to the beam set to a particular communicationlink.

Aspects of the invention include a method of resource reuse in awireless communication system. The method includes determining terminalinformation, determining a first beam in a first beam set from aplurality of beam sets based upon the terminal information, each beam inthe first beam set associated with a subset of resources of a pluralityof resources, and transmitting signals utilizing the first beam in thefirst beam set on at least some of the subset of resources.

Aspects of the invention include a method of resource reuse in awireless communication system. The method includes receiving a pluralityof signals that are transmitted over at least some of a plurality ofsubstantially orthogonal resources, determining at least one qualitymetric based upon the plurality of signals, transmitting a communicationto a base station based on the at least one quality metric, andreceiving a signal associated with a beam of a beam set and with asubset of the plurality of orthogonal resources associated with the beamset.

Aspects of the invention include a method of resource reuse in awireless communication system. The method includes determining a beam infirst beam set supporting a communication link, each beam in the firstbeam set associated with a resource, transmitting signals within thebeam in the first beam set, and transitioning the signals from the beamin the first beam set to a beam in a second beam set, each beam in thesecond beam set associated with a resource that is substantiallyorthogonal to a resource associated with the first beam set.

Aspects of the invention include a method of resource reuse in awireless communication system. The method includes receiving signalsacross multiple substantially orthogonal resources, determining aquality metric for each of the substantially orthogonal resources,transmitting a communication to a base station based on the qualitymetrics, and receiving a beamformed signal utilizing at least one of themultiple orthogonal resources based on the communication.

Aspects of the invention include an apparatus configured to supportresource reuse in a wireless communication system that includes atransmitter configured to generate a transmit signal utilizing at leastone of a plurality of resources based on one or more control signals, aresource controller configured to generate the one or more controlsignals to the transmitter controlling a selection of the at least oneof a plurality of resources, an encoder coupled to the transmitter andthe resource controller and configured to encode the transmit signal toa first beam from a first beam set associated with the at least one ofthe plurality of resources, and a plurality of antennas coupled to theencoder and configured to broadcast the encoded transmit signal in thefirst beam.

Aspects of the invention include an apparatus configured to supportresource reuse in a wireless communication system that includes areceiver configured to receive a plurality of signals corresponding to aplurality of beamformed signals, the plurality of signals associatedwith at least two distinct resources, a baseband processor configured toprocess at least a portion of the plurality of signals based on acorresponding resource, and configured to generate at least one qualitymetric for received signals of each resource, and a resource controllerconfigured to control the receiver and baseband processor to support aparticular resource.

Aspects of the invention include an apparatus configured to supportresource reuse in a wireless communication system that includes meansfor determining terminal information, means for determining a first beamin a first beam set from a plurality of beam sets based upon theterminal information, each beam in the first beam set associated with asubset of resources of a plurality of resources, and means fortransmitting signals utilizing the first beam in the first beam set onat least some of the subset of resources.

Aspects of the invention include an apparatus configured to supportresource reuse in a wireless communication system that includes meansfor receiving a plurality of signals that are transmitted over at leastsome of a plurality of substantially orthogonal resources, means fordetermining at least one quality metric based upon the plurality ofsignals, means for transmitting a communication to a base station basedon the at least one quality metric, and means for receiving a signalassociated with a beam of a beam set and with a subset of the pluralityof orthogonal resources associated with the beam set.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, objects, and advantages of embodiments of the disclosurewill become more apparent from the detailed description set forth belowwhen taken in conjunction with the drawings, in which like elements bearlike reference numerals.

FIG. 1 is a simplified functional block diagram of an embodiment of awireless communication system.

FIG. 2 is a simplified functional block diagram of an embodiment of atransmitter and receiver in a multiple access wireless communicationsystem.

FIG. 3 is a simplified functional block diagram of an embodiment of atransmitter system supporting resource reuse in SDMA beams.

FIG. 4 is a simplified diagram of an embodiment of beam patterns forSDMA beam sets.

FIG. 5 is a simplified diagram of an embodiment of beam patterns forsectorized SDMA beam sets.

FIG. 6 is a graph of user geometry for various particular embodiments offrequency reuse SDMA.

FIG. 7 is a simplified functional block diagram of an embodiment of areceiver system supporting resource reuse in SDMA beams.

FIGS. 8A-8C are simplified flowcharts of embodiments of methods ofresource reuse in a SDMA system.

FIG. 9 is a simplified functional block diagram of an embodiment of atransmitter system supporting resource reuse in SDMA beams.

FIG. 10 is a simplified functional block diagram of an embodiment of areceiver supporting resource reuse in SDMA beams.

DETAILED DESCRIPTION OF THE INVENTION

A wireless communication system can implement SDMA by providing multipleantenna beams positioned to support a predetermined coverage area. Thecommunication system can implement the antenna beams as multipledirectional antennas, beamformed or beamsteered antennas, and the like,or a combination thereof. The multiple antenna beams can be configuredto support a predetermined coverage area. The predetermined coveragearea can be substantially omni-directional, or can be limited, such as asector of a coverage area that is modeled as being circular orhexagonal.

Each of the multiple beams can support a substantially independent areawithin the predetermined coverage area. Furthermore, the beams can beassociated with beam sets, where each beam set supports thepredetermined coverage area. The beams of a beam set are substantiallynon-overlapping, such that transmissions in one beam do notsubstantially contribute to interference in an adjacent beam of the samebeam set. The beam sets can be configured such that a major beam from afirst set occurs within a boundary of one or more adjacent beams from asecond set. In this manner the first beam set provides strong beamcoverage in areas of weak beam coverage from the second beam set. A beamset need not be a plurality of independent beams, but can be a pluralityof different beam axes to which a beam can be steered using, forexample, transmit signal weighting to beamsteer the broadcast signal.

The wireless communication system can also associate a resource witheach beam set. Ideally, the resources associated with each beam set issubstantially orthogonal to a similar resource associated with any otherbeam set. Examples of orthogonal resources include, but are not limitedto, frequency, time, coding, interlacing, and the like, or somecombination thereof.

The wireless communication system can determine a servicing beam andassociated beam set and orthogonal resource for each communication link.The wireless communication system can determine that a communicatingdevice is transitioning towards a beam edge. For example, thecommunicating device can provide a feedback or overhead messagereporting one or more metrics, messages, or other information that isrelated to position within a beam of a beam set.

The wireless communication system can transition the communication linkfrom an edge of a beam in a beam set having an associated orthogonalresource to a second beam set having a beam with a major lobeoverlapping the present beam edge. The beam in the second beam set has adifferent associated orthogonal resource. The communication systemtransitions the communication link from a beam in the first beam set andfirst orthogonal resource to a beam in a second beam set with a secondorthogonal resource.

In one embodiment, a cellular wireless communication system canimplement SDMA in one or more base stations using beamformedomni-directional antennas. Using beamforming technique, omni antennascan be used with space-division multiple access (SDMA) technique tocreate beams at different spatial direction to achieve virtualsectorization of a cellular system. For example, a base station cangenerate beams using multiple omni-directional antennas to achieve peakbeam gains at 0°, 60°, and 120° and their mirror response 180°, 240°,and 300° to form 3-beam SDMA system in a cell.

It is desirable to have uniform beam coverage over the cell coveragearea. However, communication devices situated at an overlapping area oftwo beams will experience very low signal to interference ratio (SINR)due to non-separable interference from other beams which has comparablepower to the desired signal power. Therefore, such fixed beam coverageis not ideal for wireless devices positioned near a beam boundary.

The cellular wireless communication system can implement one or morecomplementary beam sets having peak beam gains positioned at the overlapof adjacent beams from a distinct beam set, and substantially midwaybetween the major axes of adjacent beams. The complementary beam setsare each associated with a distinct resource, where each resource issubstantially orthogonal to the resource associated with another beamset.

FIG. 1 is a simplified functional block diagram of an embodiment of amultiple access wireless communication system 100. A multiple accesswireless communication system 100 includes multiple cells, e.g. cells102, 104, and 106. In the embodiment of FIG. 1, each cell 102, 104, and106 may include an access point 150 that includes multiple sectors.

The multiple sectors are formed by groups of antennas each responsiblefor communication with access terminals in a portion of the cell. Incell 102, antenna groups 112, 114, and 116 each correspond to adifferent sector. For example, cell 102 is divided into three sectors,120 a-102 c. A first antenna 112 serves a first sector 102 a, a secondantenna 114 serves a second sector 102 b, and a third antenna 116 servesa third sector 102 c. In cell 104, antenna groups 118, 120, and 122 eachcorrespond to a different sector. In cell 106, antenna groups 124, 126,and 128 each correspond to a different sector.

Using beamforming or beamsteering techniques, omni antennas can be usedwith SDMA techniques to create beams at different spatial direction toachieve virtual sectorization of a cellular system. For example, a basestation can generate beams using multiple omni-directional antennas toachieve peak beam gains at 0°, 60°, and 120° and their mirror response180°, 240°, and 300° to form 3-beam SDMA system in a cell.

Each cell is configured to support or otherwise serve several accessterminals which are in communication with one or more sectors of thecorresponding access point. For example, access terminals 130 and 132are in communication with access point 142, access terminals 134 and 136are in communication with access point 144, and access terminals 138 and140 are in communication with access point 146. Although each of theaccess points 142, 144, and 146 is shown to be in communication with twoaccess terminals, each access point 142, 144, and 146 is not limited tocommunicating with two access terminals and may support any number ofaccess terminals up to some limit that may be a physical limit, or alimit imposed by a communications standard.

As used herein, an access point may be a fixed station used forcommunicating with the terminals and may also be referred to as, andinclude some or all the functionality of, a base station, a Node B, orsome other terminology. An access terminal (AT) may also be referred toas, and include some or all the functionality of, a user equipment (UE),a user terminal, a wireless communication device, a terminal, a mobileterminal, a mobile station or some other terminology.

The above embodiments can be implemented utilizing transmit (TX)processor 220 or 260, processor 230 or 270, and memory 232 or 272, asshown in FIG. 2. The processes may be performed on any processor,controller, or other processing device and may be stored as computerreadable instructions in a computer readable medium as source code,object code, or otherwise.

FIG. 2 is a simplified functional block diagram of an embodiment of atransmitter and receiver in a multiple access wireless communicationsystem 200. At transmitter system 210, traffic data for a number of datastreams is provided from a data source 212 to a transmit (TX) dataprocessor 214. In an embodiment, each data stream is transmitted over arespective transmit antenna. TX data processor 214 formats, codes, andinterleaves the traffic data for each data stream based on a particularcoding scheme selected for that data stream to provide coded data.

TX data processor 214 can be configured to apply beamforming weights tothe symbols of the data streams based upon the location of the user towhich the symbols are being transmitted and the antennas from which thesymbol is being transmitted. In some embodiments, the beamformingweights may be generated based upon channel response information that isindicative of the condition of the transmission paths between the accesspoint and the access terminal. The channel response information may begenerated utilizing CQI information or channel estimates provided by theuser. Further, in those cases of scheduled transmissions, the TX dataprocessor 214 can select the packet format based upon rank informationthat is transmitted from the user.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions provided by processor 230. In some embodiments, the numberof parallel spatial streams may be varied according to the rankinformation that is transmitted from the user.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(for example, for OFDM). TX MIMO processor 220 then provides NT symbolstreams to NT transmitters (TMTR) 222 a through 222 t. In certainembodiments, TX MIMO processor 220 applies beamforming weights to thesymbols of the data streams based upon the user to which the symbols arebeing transmitted and the antenna from which the symbol is beingtransmitted from that users channel response information.

Each transmitter 222 a through 222 t receives and processes a respectivesymbol stream to provide one or more analog signals, and furtherconditions (e.g., amplifies, filters, and upconverts) the analog signalsto provide a modulated signal suitable for transmission over the MIMOchannel. NT modulated signals from transmitters 222 a through 222 t arethen transmitted from NT antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254. Eachreceiver 254 conditions (e.g., filters, amplifies, and downconverts) arespective received signal, digitizes the conditioned signal to providesamples, and further processes the samples to provide a corresponding“received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide the rank number of “detected” symbolstreams. The processing by RX data processor 260 is described in furtherdetail below. Each detected symbol stream includes symbols that areestimates of the modulation symbols transmitted for the correspondingdata stream. RX data processor 260 then demodulates, deinterleaves, anddecodes each detected symbol stream to recover the traffic data for thedata stream. The processing by RX data processor 260 is complementary tothat performed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to recover the CQI reported by the receiver system. The reported CQIis then provided to processor 230 and used to (1) determine the datarates and coding and modulation schemes to be used for the data streamsand (2) generate various controls for TX data processor 214 and TX MIMOprocessor 220.

FIG. 3 is a simplified functional block diagram of an embodiment of atransmitter system 300 supporting resource reuse in SDMA beams. Thetransmitter system 300 of FIG. 3 can be an embodiment of, for example,the transmitter system of FIG. 2 or a transmitter system within a basestation or subscriber station of the wireless communication system ofFIG. 1.

The transmitter system 300 includes a transmitter 310 configured togenerate one or more RF signal streams based on data or information. Thetransmitter 310 can be configured to receive one or more baseband signalstreams and process the one or more baseband signal streams to one ormore RF signal streams. For example, the transmitter 310 can beconfigured to generate one or more OFDM symbols based on the one or morebaseband signal streams, and at least one OFDM subcarrier within asymbol can be configured to support a particular communication link. Thetransmitter 310 frequency converts the one or more OFDM symbols toassociated RF operating bands.

The transmitter 310 includes support for one or more substantiallyorthogonal resources. The transmitter 310 can be configured to processthe signal stream supporting a particular communication link toselectively utilize one or more of the substantially orthogonalresources based on one or more signals provided to a control input.

The transmitter 310 couples the output RF signals to a beamformingencoder 320 configured to beamform the RF signal using multiple antennas340 ₁-340 _(N). The multiple antennas 340 ₁-340 _(N) can be an array ofsubstantially similar antennas or can include multiple different antennatypes, where each antenna type provides a distinct antenna pattern. Forexample, the antennas 340 ₁-340 _(N) can be an arrangement of multipleomni-directional antennas. In another example, the antennas 340 ₁-340_(N) can be an arrangement of directional antennas, or a combination ofone or more directional antennas with one or more omni-directionalantennas.

A timing and synchronization module 350 is configured to provide timingsignals to control event timing within the transmitter system 300. Thetiming and synchronization module 350 can include, for example, a clocksource and a control loop that synchronizes the clock source to anexternal time reference. For example, the timing and synchronizationmodule 350 can be configured to synchronize OFDM symbols generated bythe transmitter system 310 to a system time. Additionally, the OFDMsymbols generated by the transmitter system 300 can be arranged in setsof slots, frames, or some other arrangement, and the timing andsynchronization module 350 can maintain synchronization for eacharrangement of symbols.

A resource controller 360 can be configured to generate one or morecontrol signals that control the beam set and associated resources foreach communication link. The resource controller 360 can include abeamforming codebook 362 that holds the vector values used to beamformthe signal stream using the multiple antennas 340 ₁-340 _(N). Forexample, the beamforming codebook 362 can include a vector of complexweights, where each complex weight in a vector weights a signal for acorresponding antenna. As an example, the beamforming codebook 362 caninclude one or more storage devices, such as solid state memory.

The beamforming encoder 320 weights each sample in the signal streamwith an appropriate weight vector from the beamforming codebook 362. Thebeamforming encoder 320 can include, for example, a signal splitter thatis configured to split the signal from the transmitter 310 to N copiesfor N parallel signal paths, where N represents the number of antennas340 ₁-340 _(N). The beamforming encoder 320 can include a multiplier orscaler in each antenna signal path that operates to multiply thetransmitter signal by a weight from a beamforming codebook 362 vector.

The beamforming encoder 320 can apply the beamforming weights to a timedomain signal representation or to a frequency domain representation.Additionally, although the beamforming encoder 320 of FIG. 3 operates onthe output of the transmitter 310, in other embodiments the beamformingencoder 320 can be integrated with the transmitter 310 and can operateon baseband signals, prior to frequency conversion to RF.

The resource controller 360 determines which vector from the beamformingcodebook 362 to apply to a particular sample, and supplies the vector tothe beamforming encoder 320. The resource controller 360 or thebeamforming encoder 320 can use a reference signal from the timing andsynchronization module 350 to align the timing of the vector with theappropriate signal sample.

The resource controller 360 can organize or otherwise track thebeamforming vectors in the beamforming codebook 362 according topredetermined beam sets. Each beam set can include a sufficient numberof beams to support a predetermined coverage area, and corresponds tobeamforming vectors used to configure beams in the beam set. Each beamset can be configured to be substantially complementary to another ofthe beam sets, such that the beam sets to not provide substantially thesame coverage within the coverage area.

In one embodiment, the major axis of a beam from a first beam set liessubstantially midway between the major axes of adjacent beams from atleast one other beam set. For example, in an embodiment having two beamsets, a major axis of a beam from the first beam set is positionedsubstantially midway between the major axes of the two adjacent beamsfrom the second beam set. Similarly, in embodiments having three beamsets, the major axis of a beam from a first beam set lies substantiallymidway between the major axes of adjacent beams, where one of theadjacent beams is from a second beam set and another of the adjacentbeams is from a third beam set. The location of the beams in the variousbeam sets can be similarly determined for any number of beam sets.

Each beam set is associated with one or more orthogonal resources, wherethe term orthogonal, in the context of resources associated with beamsets, includes substantially orthogonal and quasi-orthogonal. Theorthogonal resources can include, but are not limited to, frequency,time, code, and the like, or some combination thereof.

As described above, the major axis of a beam from a beam set typicallyis positioned to lie within a null or otherwise weak coverage area ofanother beam set. The number of beams occupying a null between adjacentbeams of a beam set is equal to one less than the number of beam sets,and relates directly to the rate of resource reuse. In general, thereuse rate is the inverse of the number of distinct beam sets and isequal to 1/K, where K represents the number of beam sets.

FIG. 4 is a simplified diagram of an embodiment of antenna patterns formultiple SDMA beam sets 400. The multiple SDMA beam sets 400 include twocomplementary beam sets, with each beam set having six major beam axesto support a substantially round coverage area.

A first beam set includes beams 420 ₁-420 ₆ having major axis atapproximately 0, 60, 120, 180, 240, and 300 degrees. A second beam setincludes beams 410 ₁-410 ₆ having major axis at approximately 30, 90,150, 210, 270, and 330 degrees. Each beam set is associated with asubstantially orthogonal resource. The two beam sets provide a resourcereuse of ½. For example, the first beam set is illustrated as associatedwith a first frequency, F1, while the second beam set is illustrated asassociated with a second frequency, F2. The frequencies, F1 and F2, canrepresent a frequency or frequency band. For example, the frequencies F1and F2 can represent distinct sets of subcarrier frequencies that aresubstantially orthogonal over a sampling rate and integration period.

The beams and beam sets can be configured to support virtually anycoverage area, and the coverage are need not coincide with the entirecoverage area supported by a base station. FIG. 5 is a simplifieddiagram 500 of an embodiment of beam patterns for sectorized SDMA beamsets.

In the embodiment of FIG. 5, two beams sets, S1 and S2, are configuredto support a coverage are that can be a sector of an entire coveragearea supported by a base station. The sector is approximately bounded bya first sector boundary 502 and a second sector boundary 504. In atypical sectorized coverage area, the first sector boundary 502 and thesecond sector boundary 504 span a coverage area of approximately 120degrees.

The first beam set, S1, includes first and second beams 510 ₁ and 510 ₂that support the sector. The second beam set, S2, includes first andsecond beams 520 ₁ and 520 ₂ that support the sector and that arepositioned to complement the beams of the first beam set.

The resource controller 360 includes a beam set controller 364 that isconfigured to track the beam set and beam associated with a particularcommunication link. The beam set controller 364 ensures that theappropriate codebook vectors corresponding to an active beam set areused for a particular communication link. Additionally, the beam setcontroller 360 controls one or more parameters related to the one ormore orthogonal resources associated with the beam sets.

In one embodiment, the orthogonal resource associated with the beamssets is frequency. The transmitter 310 can be configured to generateOFDM symbols with a first set of subcarriers when supporting a firstbeam set and can be configured to generate OFDM symbols using a secondset of subcarriers that is substantially orthogonal to the first set ofsubcarriers, based on the symbol time and data rate. The beam setcontroller 364 can be configured to control the transmitter 310 tofrequency convert the OFDM symbol to an RF frequency that depends atleast in part on the active beam set for the communication link.Alternatively, the transmitter 310 can be configured to generate twoorthogonal OFDM symbols, each corresponding to a distinct beam set, andthe beam set controller 364 can be configured to control the transmitterto selectively populate one of the OFDM symbols based on the active beamset associated with the communication link.

Where the orthogonal resource is time, the beam set controller 364 canbe configured to control the time in which the transmitter 310 generatesan output signal for a data sample, depending on the active beam setassociated with the data sample. Similarly, if the orthogonal resourceis code, the beam set controller 364 can control which code of aplurality of orthogonal codes the transmitter 310 uses to encode aparticular data sample, based on the active beam set allocated to thedata sample.

The transmitter 310 can be configured to generate distinct pilot signalsfor each of the beams in each of the beam sets. In another embodiment,the transmitter can be configured to generate a pilot signal that isshared among multiple beams in a particular beam set. The beamformingcodebook 362 can be configured to provide or otherwise make accessibleto the transmitter 310 beamforming vectors that are used to beamform thepilot signals to the appropriate beams. The beamforming vectors can alsoapply additional weights to the pilot signals to identify which of thebeams the pilot signal occupies. The additional weights can be, forexample, a distinct complex weight associated with each beam. In anotherembodiment, the beam set controller 364 can control the transmitter 310to introduce further processing of pilot signals in order to allowidentification of the beam from which the pilot signal originates. Theadditional processing can be, for example, a rotation, time delay,conjugation, or some other processing or combination of processing. Inanother embodiment, each antenna can be configured to generate adistinct pilot signal.

The transmitter system 300 also includes a receiver 330 configured toreceive spatial information from a destination device, such as asubscriber station. The receiver 330 is depicted as being coupled to adistinct receive antenna 332. However, in other embodiments, thereceiver 330 can utilize some or all of the antennas 340 ₁-340 _(N) usedin beamforming the transmit signals.

The receiver 330 can receive a communication from each supported devicewithin the coverage area of the transmitter system 300. Thecommunication indicate the beam in which the device resides, and canprovide some indication of the position within the beam. Thecommunication need not provide the information directly, but may providemessages, metrics, or parameters that the receiver 330 uses to determinethe beam and location within the beam. For example, the device cancommunicate an indication of the beam identity based on the receivedpilot signals, and can provide a signal quality metric that is generallyindicative of a proximity to a beam edge.

The receiver 330 can process the received communication in order todetermine whether to initiate a beam set handoff. Alternatively, thereceiver 330 can couple the received communication to the resourcecontroller 360 and the resource controller can determine whether toinitiate beam set handoff for the device.

FIG. 6 is a graph 600 of user geometry for particular embodiments offrequency reuse SDMA. The graph 600 illustrates improved user geometry(long term SINR) in ½ reuse 620 and ⅓ reuse 630 SDMA cases compared tono-reuse 610 fixed beam SDMA. Depending on the antenna elements, a gainin the order of 3˜5 dB can be seen. To further improve the usergeometry, the order of beam set mapping to frequency reuse set, i.e.{Si}→{Fi} can be rotated for different cell, so for two adjacent cells,two different beam sets at different orientations will be used on thesame frequency set Fi. This arrangement can avoid head-to-headinterference from beams from a neighboring cell, and may improve theworst user's geometry.

A reuse embodiment utilizing time or code as the orthogonal resourceassociated with the beam sets can implement a rotation of the beam setsof neighboring cells or coverage areas such that the time intervals orcodes of adjacent cells or base station coverage areas are alsoorthogonalized in the appropriate dimensions with respect to each other.Similarly, reuse embodiments utilizing a combination of orthogonalizingresources can limit the overlap of similar resources in adjacentcoverage areas.

As an example of the operation of beam handoffs in a frequency reusesystem, the transmitter system 300 of FIG. 3 can be implemented within abase station of the wireless communication system of FIG. 1. Thetransmitter system 300 can be configured to generate signals within twodistinct and complementary beam sets. The transmitter system 300 canimplement frequency as the orthogonal resource for the beam sets.Additionally, the transmitter system 300 can transmit at least one pilotsignal in each beam of a beam set, and the pilot signal in a beam canidentify the beam to which it corresponds.

A destination device, such as a subscriber station within a coveragearea of the transmitter system 300, receives the pilot signals anddetermines which of the beams and corresponding beam sets it resides.The operation of a receiver system in a destination device is describedin further detail with respect to FIG. 7.

The destination device can generate and transmit to the transmittersystem 300 a communication indicative of the beam set, beam, and signalquality within the beam. The destination device can, for example,transmit a signal quality metric within the communication for one ormore beams and associated beam sets. The receiver 330 of the transmittersystem 300 receives the communication from the destination device anddetermines a preferred beam and associated beam set in which thedestination device is positioned. The preferred beam can be, forexample, the beam and associated beam set for which the destinationdevice experiences the best received signal quality.

The receiver 330 reports the beam and beam set information to theresource controller 360. The beam set controller 364 determines theappropriate resource control signals to provide to the transmitter 310in order to configure the transmitter for the appropriate beam set. Theresource controller 360 selects the vector or other appropriate codebookentry from beamforming codebook 362 to encode signals directed to thedestination device.

The beamforming encoder 320 encodes the signals directed to thedestination device using the appropriate codebook entry to beamform thecommunication using the multiple antennas 340 ₁-340 _(N).

The receiver 330 monitors communications from the destination device todetermine whether to handoff the communications to the destinationdevice to another beam and associated beam set. The receiver 330 can,for example, compare the signal quality metrics corresponding to one ormore beams. The receiver 330 can determine whether to initiate a beamhandoff based on the comparison. For example, the receiver 330 caninitiate a beam handoff if the signal quality metric for an adjacentbeam exceeds the signal quality metric of the present serving beam by anamount greater than or equal to a predetermined handoff threshold. Thecomplementary configuration of the various beam sets typically resultsin a beam set handoff when a beam handoff occurs.

The resource controller 360 can initiate a beam handoff by communicatingan impending beam handoff to the transmitter 310, such that thetransmitter 310 can schedule the beam handoff and communicate detailsregarding the beam handoff to the destination device. The transmitter310 can communicate, for example, the timing and beam resources for thebeam handoff. As an example, the transmitter 310 may implement beamhandoffs at predetermined timing boundaries, such as a frame boundary.The transmitter 310 communicates the frame boundary that the beamhandoff will occur and communicates the frequency, timing, code, orother resource associated with the beam set for which communications arebeing handed.

FIG. 7 is a simplified functional block diagram of an embodiment of areceiver system 700 supporting resource reuse in SDMA beams. Thereceiver system 700 can be implemented, for example, within a subscriberstation of FIG. 1. The receiver system 700 is configured to monitor oneor more beam sets in a coverage area supported by multiple beam sets.The receiver system 700 is configured to transmit a communication to atransmitter system that is indicative of one or more beams in one ormore beam sets that can support a communication link with the receiversystem 700.

The receiver system 700 includes a receiver 710 configured to receivethe one or more beamformed signals via an antenna 702. The receiver 710filters, amplifies, and frequency converts the received signals tobaseband signals.

The receiver 710 can receive one or more timing and synchronizationsignals from a timing and synchronization module 730 to assist insynchronizing the receiver 710 with the received signal. For example,communications between the receiver system 700 and a correspondingtransmitter system may be implemented as Time Division Duplex (TDD) orTime Division Multiplex (TDM) communications, and the timing andsynchronization module 730 can operate to maintain the timing of thereceiver system 300 relative to a system time.

The receiver 710 can also be configured to receive and process signalsfrom multiple beams, corresponding to multiple beam sets. The receiver710 can process all of the received signals such that the receiversystem 700 can report signal metrics or some other signal qualityinformation for an active beam as well as one or more candidate beams,which may be associated with one or more alternative beam sets.

The receiver system 700 includes a beam set/resource controller 740 thatis configured to control the receiver 710 to enable the receiver 710 toreceive and process the signals on the multiple beam sets. For example,the beam set/resource controller 740 can track a frequency, timing, orsome other resource or combination of resources associated with themultiple beam sets. The beam set/resource controller 740 configures thereceiver 710 to process the received signals according to each of thebeam set resources. The beam set/resource controller 740 can beconfigured to control the receiver 710 to process the different beamsets corresponding to different resources sequentially or concurrently,depending on the resources differentiating beam sets. For example, thebeam set/resource controller 740 can control the receiver 710 to processreceived signals from distinct beam sets sequentially where the resourceassociated with the beam sets is a distinct time. The beam set/resourcecontroller 740 can control the receiver 710 to process received signalsfrom distinct beam sets concurrently, where the resource associated withthe beam sets is frequency or code. Of course, the beam set/resourcecontroller 740 can control the receiver 710 to process received signalsdistinct beam sets sequentially, even if the signals from the differentbeam sets can be processed concurrently.

The receiver 710 couples the baseband signals resulting from processingof the received signals to a baseband processor 720 for furtherprocessing. The baseband processor 720 can be configured to process thereceived signals from an active communication link to recover underlyingdata or information. The baseband processor 720 can be configured tocouple the data and information to an appropriate destination deviceoutput port (not shown).

The baseband processor 720 can also be configured to generate thecommunication to the transmitter system having the metric or qualityassessment of the various beams and beam sets. The baseband processor720 can include, for example, a pilot processor 722 and a beam qualitymodule 724.

The pilot processor 722 can be configured to process the pilot signalsin the multiple beams corresponding to multiple beam sets. The pilotprocessor 722 can be configured to generate a quality metric based onthe processed pilot signals, or can couple pilot information to the beamquality module 724 where a beam quality metric is generated for theactive beam an done or more candidate beams. A candidate beam can be,for example, a beam adjacent to the active beam for which the receiversystem 700 monitors for the possibility of handoff.

The pilot processor 722 may also determine an estimate of the channelcorresponding to each of the beams, and may generate a message to thetransmitter system indicative of the channel for each beam. The pilotprocessor 722 can also be configured to process pilot signals withsubstantially no knowledge of the originating beam, and report a metricrelating to the received pilot signals back to the transmitter system.The transmitter system can determine the appropriate beam based on thereported pilot metrics and may select the appropriate beam set and beam.

The beam quality module 724 can determine a beam quality metric basedon, for example, the results of the pilot processing. The beam qualitymodule 724 can alternatively, or additionally, determine a beam qualitymetric based on a signal quality in each of multiple received beams. Thevarious signal quality metrics can, for example, correspond to multiplebeam sets, each beam set associated with at least one distinct resource.The signal quality metrics can include, for example, a received signalstrength indication, a signal to noise ratio, a symbol error rate, andthe like, or some other signal quality metric or combination of signalquality metrics.

The baseband processor 720 can utilize the information from the pilotprocessor 722 and the beam quality module 724 to generate acommunication to the transmitter system indicative of beam quality. Inan embodiment, the baseband processor 720 can generate a communicationincluding all of the information received from the pilot processor 722and beam quality module 724. In another embodiment, the basebandprocessor 720 can generate a communication identifying a preferred beamand beam set. In another embodiment, the baseband processor 720 cangenerate a communication identifying a preferred codebook entry orpreferred beam weights.

The baseband processor 720 couples the communication to a transmitter750. The transmitter 750 processes the communication for transmission tothe transmitter system. The transmitter 750 can, for example, upconvertthe communication to an RF band and process the communication to theappropriate air interface format.

FIGS. 8A-8C are simplified flowcharts of embodiments of methods ofresource reuse in a SDMA system. FIGS. 8A and 8B illustrate methods ofresource reuse that can be implemented in a transmitter system, and FIG.8C illustrates a method of resource reuse that can be implemented withina receiver system.

FIG. 8A is a flowchart of an embodiment of a method 800 for assigning auser device to a beam in a wireless communication environment inaccordance with one or more embodiments presented herein. The spatialrelationship between the user device and the base station or some otherterminal information is determined (block 810). The location of the userdevice can be determined based upon the spatial signal of the basestation-user device pair. Alternatively, the user device can include aglobal positioning system (GPS) capable of determining the location ofthe user device. The appropriate beam for the user is then selected orotherwise determined based upon the terminal information, which caninclude the position or location of the terminal (block 812).

In certain aspects, the appropriate beam is selected based upon userpositioning. In other aspects, both blocks 810 and 812 may be performedby a single block responsive to information from a user indicating thebeam to use. This may be performed by, for example, selecting a beamassociated with a particular codebook entry.

The beam is then associated with the additional orthogonal resourceassigned to the beam (block 814). Each beam in a beam set can beassociated with a subset of the orthogonal resources. The additionalorthogonal resource may be, for example, a time period not utilized fortransmission on adjacent beams, an orthogonal or quasi-orthogonal codenot utilized for transmission on adjacent beams, or a set of subcarriersassociated with the beam. The associated orthogonal resource may varyover time due to channel conditions for a given beam, the number ofusers assigned to the beam, combinations thereof or some otherparameters. Also, in some cases, the amount of orthogonal resourcesassigned to a given beam may vary over time. That is, the number ofsubcarriers per subset or the length or number of time periods may vary.

The beam with the associated orthogonal resource can be transmitted orotherwise broadcast to the user device. As the terminal informationchanges, the base station may transition the transmission of signalsfrom a first beam of a first beam set to a beam from another beam setdistinct from the first beam set. The different beam sets may beassociated with different subsets of orthogonal resources.

FIG. 8B is a flowchart of an embodiment of a method 802 of resourcereuse that can be implemented within a transmitter system, such as thetransmitter system of FIG. 3 or a transmitter system in a base stationof FIG. 1.

The method 802 begins at block 820. The transmitter system is alreadyconfigured to support communications with a receiver system over acommunication link on a beam of a beam set. At block 820, thetransmitter system receives the communication having the one or moresignal quality metrics or associated information from the receiversystem.

The transmitter system proceeds to block 822 and determines, based atleast in part on the received communication, the preferred beam andassociated beam set. The transmitter system proceeds to decision block830 and determines whether to update the beam and beam set servicing thereceiver system.

The transmitter system can, for example, initiate a beam handoffimmediately upon sensing that a preferred beam is different from acurrent beam serving the receiver system. In another embodiment, thetransmitter system may utilize some threshold or hysteresis in thedecision to initiate a beam handoff, in order to reduce the possibilityof rapidly toggling between beam assignments. For example, thetransmitter system may initiate a beam handoff when the signal qualityof a proposed beam exceeds the signal quality of the serving beam bysome predetermined threshold. In another example, the transmitter systemmay initiate a beam handoff when the signal quality of a proposed beamexceeds the signal quality of the serving beam in excess of a hysteresistime period.

Once the transmitter system determines that a beam handoff is to beinitiated, the transmitter system determines if the beam handoffrequires an associated handoff of the serving beam set.

If no beam set handoff is required, such as when no beam handoff isscheduled or when a beam handoff to a serving beam set is scheduled, thetransmitter system proceeds from decision block 830 to block 832 andcontinues to support the present resource allocation. That is, because abeam set handoff is not scheduled, the transmitter system does not needto change the associated resources. The transmitter system may updatethe beam weights from the codebook, if a beam handoff within the samebeam set is desired. The transmitter system returns to block 820 tocontinue to monitor communications from the receiver system.

If the transmitter system determines at decision block 830 that a beamset handoff is desired, the transmitter system proceeds to block 840. Atblock 840, the transmitter system initiates a beam set handover. Thetransmitter system can communicate the timing of the beam set handoffand the resources associated with the updated beam set to the receiversystem. The transmitter system can communicate the information to thereceiver system using an overhead channel on the current resource andbeam set allocation.

The transmitter system proceeds to block 842 and updates the beamformingweights by selecting the appropriate codebook entry. The application ofthe updated beamforming weights to the signal results in the signalbeing beam formed by the multiple transmit antennas.

The transmitter system proceeds to block 844 and revises the resourcesutilized in the communication link to correspond with the resourcesassociated with the beam set. At a handover boundary, for example aframe boundary, the transmitter system directs a handover ofcommunications with the receiver system to the new beam in the new beamset. The transmitter system updates the beam set and the associatedresources corresponding to the particular communication link. Thetransmitter system can update, for example, the frequency, time slot,code, or some other resource associated with the beam set. Thetransmitter system returns to block 820 to monitor communications fromthe receiver system.

FIG. 8C is a flowchart of an embodiment of a method 804 of resourcereuse. The method 804 can be implemented, for example, by the receiversystem of FIG. 7 and may be implemented in a subscriber system of thewireless communication system of FIG. 1.

The method 804 begins at block 850 where the receiver system receivessignals over multiple resources. The multiple resources correspond tothe resources associated with each of the different beam sets supportedby the transmitter system. The receiver system can receive the signalswith the different resources concurrently, sequentially, or according toa predetermined schedule or algorithm.

The receiver system proceeds to block 852 and determines a qualitymetric for each of the received signals based on the beam set resources.For example, the receiver system can determine a quality metric based onthe particular received signals using the resources for a beam set, andmay not associate a quality metric with any particular beam of a beamset. Alternatively, the receiver system may have the ability to discerna beam and corresponding beam set for the received signals, and can beconfigured to generate a quality metric for multiple beams and beamsets. For example, the receiver system may receive multiple pilotsignals, and may be able to determine a particular beam of a beam setbased on the received pilot signals. In such an embodiment, the receiversystem may generate a quality metric for multiple beam and beam setpairs. The quality metric can be virtually any information from whichthe transmitter system can correlate communication link performance. Forexample, the quality metric can be a signal to noise ratio within a beamof a beam set, a received signal strength, a channel estimate, or someother information.

The receiver system proceeds to block 854 and transmits the one or morequality metrics to the transmitter system, which may include the basestation serving the coverage area in which the receiver system resides.Alternatively or additionally, the receiver system can communicate adesired beam and beam set to the transmitter system.

The receiver system proceeds to decision block 860 and determines if abeam and beam set handoff has been initiated. The beam and beam sethandoff can be initiated as a result of the most recent communication ofquality metrics or can be based on one or more past communications. Thetransmitter system can communicate a message, command, or instruction tothe receiver system initiating a beam and beam set handoff and a time,boundary, or event associated with the handoff.

If the receiver system determines that no beam set handoff is scheduled,the receiver system proceeds from decision block 860 back to block 850and continues to monitor received signals. In some embodiments, thereceiver need not have any knowledge of the particular beam in which itis operating. It only needs to operate with the resources associatedwith the active beam set. Thus, the receiver system need not alter anysignal processing when no beam set handoff occurs.

If the receiver system determines at decision block 860 that a beam sethandoff is scheduled, the receiver system proceeds to block 870. Atblock 870, the receiver system determines the timing and resourcesassociated with the beam set handover. The receiver system can, forexample, receive the beam set and handover timing information. Thereceiver system can receive a message controlling the resourcesassociated with a beam set or can include a look up table in memory thatassociates the resources with the beam sets. The receiver system cansynchronize the resource update with the timing of the handover.

The receiver proceeds to block 880. At block 880 the receiver systemcontrols the appropriate portion of the receiver system to transition tothe resource associated with the updated beam set at the handoverinstance. For example, where the distinct resource associated with thebeam sets includes a time allocation, the receiver system canresynchronize to the appropriate time slot. Similarly, where thedistinct resource associated with the beams sets is frequency, thereceiver system can update a local oscillator frequency that is used tofrequency convert the received signal from the updated frequency tobaseband. The receiver system then returns to block 850 to receive andprocess signals with the new beam set and resource allocation.

FIG. 9 is a simplified functional block diagram of an embodiment of atransmitter system 1100 supporting resource reuse in SDMA beams. Thetransmitter system 1100 includes a means for transmitting a signal 1110that includes a means for generating a transmit signal.

A means for receiving 1130 can be configured to receive, via a receiveantenna 1132, one or more signals from a signal source, such as a userterminal, and can determine terminal information based on the receivedsignals. The terminal information can include, for example a location ofa terminal in a coverage area or can include an angular position of aterminal in a coverage area.

The transmitter system 1100 also includes a means for timing andsynchronization 1150 coupled to the means for transmitting andconfigured to provide one or more timing signals to synchronize orotherwise control the timing of operations within the means fortransmitting a signal. The means for timing and synchronization 1150 canoperate in conjunction with the means for receiving 1130 to determinethe terminal information.

A means for controlling a resource allocation 1160 includes means forbeamforming 1162 that can include a means for storing at least onebeamforming codebook defining multiple beamforming vectors in each ofmultiple beam sets. The means for controlling a resource allocation 1160includes means for controlling a beam set that includes means fordetermining a first beam of a first beam set for supporting acommunication link, each beam of the first beam set associated with afirst resource. The first beam set can be part of a plurality of beamsets, where each beam in the first beam set is associated with a subsetof resources of a plurality of resources.

The means for controlling a resource allocation 1160 can also includemeans for determining a first beam of a second beam set for supportingthe communication link, each beam of the second beam set associated witha second resource that is distinct from the first resource, when areceived signal indicates that a beam set a handover is to occur.

A means for beamforming signals 1120 can be configured to generate aplurality of copies of a transmit signal from the means fortransmitting, and can include a means for applying a distinctbeamforming weight from a beamforming vector associated with the beamfor each of the plurality of transmit signal copies to generate weightedsignals. The means for beamforming signals 1120 couples the weightedsignals to the multiple antennas 1140 ₁-1140 _(N) for transmitting to adestination device within a coverage area.

A means for receiving a communication 1130 can receive the communicationfrom a receive antenna 1132 and can determine a beam set transitionevent based on the communication. The means for receiving acommunication 1130 can initiate a beam set handover in response to thecommunication. For example, the means for receiving a communication 1130can control the means for controlling resource allocation 1160 tocontrol the means for transmitting 1110 and means for beamforming 1120to beamform or otherwise beamsteer the transmit signals to a beam from asecond beam set using a second resource in place of using the first beamset and associated first resource.

FIG. 10 is a simplified functional block diagram of an embodiment of areceiver system 1200 supporting resource reuse in SDMA beams. Thereceiver system 1200 includes a means for receiving signals 1210 acrossmultiple substantially orthogonal resources, where the signals aretransmitted over at least a portion of the multiple substantiallyorthogonal resources. The means for receiving signals 1210 can include ameans for receiving a beamformed signal utilizing at least one of themultiple orthogonal resources based on a communication received from asignal source, such as a transmitter system or base station.

The means for receiving signals 1210 can be controlled to support eachof the multiple substantially orthogonal resources based on one or morecontrol signals from a means for controlling beam set/resource 1240. Themeans for controlling beam set/resource 1240 can include a look up tableor registers listing each of the multiple substantially orthogonalresources, and the corresponding control signals needed to control thereceiver system 1200 to support communications utilizing the resource.

A means for timing and synchronization 1230 can be configured tomaintain synchronization or timing reference that is used by the meansfor receiving signals 1210 when processing the received signals. A meansfor processing 1220 is configured to further process the signals fromthe means for receiving signals 1210. The means for processing 1220 caninclude a means for measuring or otherwise determining at least aquality metric 1224 that determines a signal quality metric for each ofthe substantially orthogonal resources. The means for processing 1220can also include a means for pilot processing 1222 that is configured toprocess received pilot signals in order to assist in generating thesignal quality metrics.

The receiver system 1200 includes a mean for transmitting acommunication 1250 configured to receive the signal quality metrics andgenerate a communication that is transmitted to a base station. Thecommunication can be the actual signal quality metrics or can be basedon the quality metrics. For example, the means for transmitting acommunication 1250 can be configured to transmit a beam set selectionindication rather than a quality metric value.

Methods and apparatus for supporting resource reuse in a SDMA systemhave been described herein. The system can support multiple beam sets,with each beam set having multiple beam supporting a predeterminedcoverage area. Each beam set can be substantially complementary to adistinct beam set, such that the major beam axes for a first beam setlie approximately midway between the major beam axes of the closestadjacent beams. The closest adjacent beams are typically from distinctbeam sets, but do not need to be from the same beam set.

Each beam set is associated with a particular resource, and theresources associated with the beam sets can be orthogonal orsubstantially orthogonal. The number of distinct beam sets andcorresponding number of substantially orthogonal resources define areuse set or reuse rate.

The complementary placement of the beams in the distinct beam setsreduces the amount of interference experienced in each beam, whileproviding substantially uniform support over the entire coverage area.

As used herein, the term coupled or connected is used to mean anindirect coupling as well as a direct coupling or connection. Where twoor more blocks, modules, devices, or apparatus are coupled, there may beone or more intervening blocks between the two coupled blocks.

The various illustrative logical blocks, modules, and circuits describedin connection with the embodiments disclosed herein may be implementedor performed with a general purpose processor, a digital signalprocessor (DSP), a Reduced Instruction Set Computer (RISC) processor, anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. A generalpurpose processor may be a microprocessor, but in the alternative, theprocessor may be any processor, controller, microcontroller, or statemachine. A processor may also be implemented as a combination ofcomputing devices, for example, a combination of a DSP and amicroprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration.

For a firmware and/or software implementation, the techniques describedherein may be implemented as instructions (for example, procedures,functions, and so on) that perform the functions described herein. Thefirmware and/or software codes may be stored in a memory and executed bya processor or processors. If implemented in software, the functions maybe stored on or transmitted over as one or more instructions or code ona computer-readable medium. Computer-readable media includes bothcomputer storage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The steps of a method, process, or algorithm described in connectionwith the embodiments disclosed herein may be embodied directly inhardware, in a software module executed by a processor, or in acombination of the two. The various steps or acts in a method or processmay be performed in the order shown, or may be performed in anotherorder. Additionally, one or more process or method steps may be omittedor one or more process or method steps may be added to the methods andprocesses. An additional step, block, or action may be added in thebeginning, end, or intervening existing elements of the methods andprocesses.

The above description of the disclosed embodiments is provided to enableany person of ordinary skill in the art to make or use the disclosure.Various modifications to these embodiments will be readily apparent tothose of ordinary skill in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the disclosure. Thus, the disclosure is not intendedto be limited to the embodiments shown herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

1. A method of resource reuse in a wireless communication system, themethod comprising: determining terminal information; determining a firstbeam in a first beam set from a plurality of beam sets based upon theterminal information, each beam in the first beam set associated with asubset of resources of a plurality of resources; transmitting signalsutilizing the first beam in the first beam set on at least some of thesubset of resources; and transitioning transmission of signals from thefirst beam to a second beam of a second beam set different than thefirst beam set, and on another subset of the resources orthogonal withrespect to the subset of resources associated with the first beam set,the another subset being associated with the second beam set, whereinpositions of the beams in the first beam set are complementary topositions of the beams in the second beam set such that a beam from thefirst beam set provides strong coverage to a weak coverage area of thesecond beam set.
 2. The method of claim 1, wherein a major axis of abeam in the second beam set is substantially midway between major axesof adjacent beams from distinct beam sets.
 3. The method of claim 1,wherein the plurality of resources comprise time slots and each subsetof time slots associated with each beam set is orthogonal with eachsubset of time slots associated with each other beam set.
 4. The methodof claim 1, wherein determining the terminal information comprisesdetermining a location of the terminal within a coverage area.
 5. Themethod of claim 1, wherein determining the first beam comprisesselecting a codebook vector corresponding to the first beam of the firstbeam set and wherein transmitting comprises weighting the signals usingthe codebook vector to generate weighted signals.
 6. The method of claim1, wherein determining terminal information comprises determining atleast one quality metric.
 7. The method of claim 6, wherein determiningat least one quality metric comprises determining an entry of a codebookreceived from the terminal.
 8. The method of claim 6, whereindetermining at least one quality metric comprises determining an entryof a codebook based upon received pilot signals from the terminal. 9.The method of claim 6, wherein determining at least one quality metriccomprises determining channel quality information.
 10. The method ofclaim 6, wherein determining at least one quality metric comprisesdetermining channel quality information based upon signals received fromthe terminal.
 11. The method of claim 1, wherein the plurality ofresources comprise subcarriers in an orthogonal frequency divisionmultiple access (OFDMA) system and wherein each subset of subcarriersassociated with each beam set is orthogonal with each subset ofsubcarriers associated with each other beam set.
 12. The method of claim1, wherein the plurality of resources comprise interlaces and eachsubset of interlaces associated with each beam set is orthogonal witheach subset of interlaces associated with each other beam set.
 13. Amethod of resource reuse in a wireless communication system, the methodcomprising: receiving a plurality of signals that are transmitted overat least some of a plurality of substantially orthogonal resources;determining at least one quality metric based upon the plurality ofsignals; transmitting a communication to a base station based on the atleast one quality metric; receiving a signal associated with a firstbeam of a first beam set and with a subset of the plurality oforthogonal resources associated with the first beam set; and receiving asignal associated with a second beam of a second beam set different fromthe first beam set, and on another subset of the plurality ofsubstantially orthogonal resources, the another subset being associatedwith the second beam set, wherein positions of the beams in the firstbeam set are complementary to positions of the beams in the second beamset such that a beam from the first beam set provides strong coverage toa weak coverage area of the second beam set.
 14. The method of claim 13,wherein transmitting the communication comprises transmitting a beam setselection indication.
 15. The method of claim 13, wherein thesubstantially orthogonal resources comprise frequencies.
 16. The methodof claim 13, wherein the substantially orthogonal resources comprisetime assignments.
 17. The method of claim 13, wherein the plurality ofsignals comprise pilot signals.
 18. The method of claim 13, whereindetermining at least one quality metric comprises determining an entryof a codebook associated with the beam.
 19. The method of claim 13,wherein determining at least one quality metric comprises determining anentry of a codebook associated with the beam set.
 20. The method ofclaim 13, wherein determining at least one quality metric comprisesdetermining channel quality information.
 21. The method of claim 13,wherein the plurality of substantially orthogonal resources comprisesubcarriers in an orthogonal frequency division multiple access (OFDMA)system and wherein each subset of subcarriers associated with each beamset is substantially orthogonal with each subset of subcarriersassociated with each other beam set.
 22. The method of claim 13, theplurality of substantially orthogonal resources comprise interlaces andeach subset of interlaces associated with each beam set is orthogonalwith each subset of interlaces associated with each other beam set. 23.The method of claim 13, wherein the plurality of substantiallyorthogonal resources comprise time slots and each subset of time slotsassociated with each beam set is substantially orthogonal with eachsubset of time slots associated with each other beam set.
 24. Anapparatus configured to support resource reuse in a wirelesscommunication system, the apparatus comprising: means for determiningterminal information; means for determining a first beam in a first beamset from a plurality of beam sets based upon the terminal information,each beam in the first beam set associated with a subset of resources ofa plurality of resources; means for transmitting signals utilizing thefirst beam in the first beam set on at least some of the subset ofresources; and means for transitioning transmission of signals from thefirst beam to a second beam of a second beam set different than thefirst beam set, and on another subset of the resources orthogonal withrespect to the subset of resources associated with the first beam set,the another subset being associated with the second beam set, whereinpositions of the beams in the first beam set are complementary topositions of the beams in the second beam set such that a beam from thefirst beam set provides strong coverage to a weak coverage area of thesecond beam set.
 25. The apparatus of claim 24, wherein the means fordetermining the first beam comprises means for selecting a codebookvector corresponding to the first beam of the first beam set and whereinthe means for transmitting comprises means for weighting the signalsusing the codebook vector to generate weighted signals.
 26. Theapparatus of claim 24, wherein the means for determining the first beamcomprises means for determining the first beam in the first beam setassociated with a first subset of resources that is substantiallyorthogonal to a second subset of resources associated with a second beamset from the plurality of beam sets.
 27. The apparatus of claim 26,wherein the first subset of resources comprises a subset of subcarriersin an orthogonal frequency division multiple access (OFDMA) system. 28.The apparatus of claim 26, wherein the first subset of resourcescomprises a subset of time slots and each subset of time slotsassociated with each beam set is orthogonal with each subset of timeslots associated with each other beam set.
 29. An apparatus configuredto support resource reuse in a wireless communication system, theapparatus comprising: means for receiving a plurality of signals thatare transmitted over at least some of a plurality of substantiallyorthogonal resources; means for determining at least one quality metricbased upon the plurality of signals; means for transmitting acommunication to a base station based on the at least one qualitymetric; means for receiving a signal associated with a first beam of afirst beam set and with a subset of the plurality of orthogonalresources associated with the first beam set; and means for receiving asignal associated with a second beam of a second beam set different fromthe first beam set, and on another subset of the plurality ofsubstantially orthogonal resources, the another subset being associatedwith the second beam set, wherein positions of the beams in the firstbeam set are complementary to positions of the beams in the second beamset such that a beam from the first beam set provides strong coverage toa weak coverage area of the second beam set.
 30. The apparatus of claim29, wherein the means for transmitting the communication comprises meansfor transmitting a beam set selection indication.
 31. The apparatus ofclaim 29, wherein the means for receiving the signals comprises meansfor receiving a plurality of pilot signals.
 32. The apparatus of claim29, wherein means for determining at least one quality metric comprisesmeans for determining an entry of a codebook associated with the beam.33. The apparatus of claim 29, wherein means for determining at leastone quality metric comprises means for determining channel qualityinformation.
 34. A non-transitory computer readable medium includinginstructions thereon that are executed by one or more processors, theinstructions comprising: instructions for determining terminalinformation; instructions for determining a first beam in a first beamset from a plurality of beam sets based upon the terminal information,each beam in the first beam set associated with a subset of resources ofa plurality of resources; instructions for transmitting signalsutilizing the first beam in the first beam set on at least some of thesubset of resources; and instructions for transitioning transmission ofsignals from the first beam to a second beam of a second beam setdifferent than the first beam set, and on another subset of theresources orthogonal with respect to the subset of resources associatedwith the first beam set, the another subset being associated with thesecond beam set, wherein positions of the beams in the first beam setare complementary to positions of the beams in the second beam set suchthat a beam from the first beam set provides strong coverage to a weakcoverage area of the second beam set.
 35. A non-transitory computerreadable medium including instructions thereon that are executed by oneor more processors, the instructions comprising: instructions forreceiving a plurality of signals that are transmitted over at least someof a plurality of substantially orthogonal resources; instructions fordetermining at least one quality metric based upon the plurality ofsignals; instructions for transmitting a communication to a base stationbased on the at least one quality metric; instructions for receiving asignal associated with a first beam of a first beam set and with asubset of the plurality of orthogonal resources associated with thefirst beam set; and instructions for receiving a signal associated witha second beam of a second beam set different from the first beam set,and on another subset of the plurality of substantially orthogonalresources, the another subset being associated with the second beam set,wherein positions of the beams in the first beam set are complementaryto positions of the beams in the second beam set such that a beam fromthe first beam set provides strong coverage to a weak coverage area ofthe second beam set.